Icebergs "calving" from Antarctic ice shelf (NASA)A new report shows that ice in Antarctica is melting at a record-breaking rate. The rise in sea levels that results from this could have catastrophic consequences for coastal cities and low-lying lands around the world. A team of 84 scientists from 44 international organizations have discovered that the rate of melting from the Antarctic ice sheet has accelerated three-fold in the last five years. They calculate that melting ice could contribute at least 25 centimetres (10 inches) towards a total global sea level rise of more than a metre (over 3 feet) by 2070. And if the entire West Antarctic ice sheet were to collapse, the oceans would rise by an astonishing 3.5 metres (11.5 feet).
Front edge of an Antarctic ice shelf (NASA)
Satellites monitoring Antarctica show that around 200 billion tons of ice are now being lost to the ocean each year as a result of melting. This is contributing about one fifth of the total rise of global sea levels, which is about 3 millimetres per year. It represents a three-fold increase since 2012. Antarctica as a whole lost more than 3 trillion tons of ice between 1992 and 2017. Most of that came from West Antarctica, where the rate of ice loss has tripled in the last 25 years.
The Antarctic ice sheet is the largest mass of ice on earth. The ice sheet forms from snow which falls on to the continent and compacts to form ice. The ice then moves under its own weight toward the edges of the continent. Most of this flows into the sea through ice streams, types of glacier.
Map of Antarctica, showing ice shelves (NSGS)
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